The answer?

When you tell people that you do open water swimming in Scotland the (almost) universal response is "why?" Until now, I haven't found an answer that seems satisfactory to the people asking the question.

I think this might be the answer. It's 7.30pm on a Tuesday; you've just had an hour swimming to the end of the loch and back, the sun is shining, you're with your friends and you want to do this.

Having said that; Chris, you are a big wimp for being in your wetsuit! (OK, maybe not; sunshine or not, the water was freezing!)